Filter for a smoking article

ABSTRACT

A filter ( 4 ) for a smoking article ( 10, 20, 30 ) comprises a flavour release segment ( 14 ) including a plurality of flavour granules. The flavour granules comprise a porous support material, a liquid flavourant, particles of plant material, and at least one binder. The plant material preferably comprises herbaceous material, more preferably herb leaf and most preferably peppermint leaf. The liquid flavourant preferably comprises at least one of: an essential oil, such as peppermint oil or spearmint oil; and natural or synthetic menthol.

The present invention relates to a flavour granule for use in a smokingarticle, a filter for a smoking article and a smoking article comprisingsuch a filter.

Filter cigarettes typically comprise a rod of tobacco cut fillersurrounded by a paper wrapper and a cylindrical filter aligned inend-to-end relationship with the wrapped tobacco rod and attachedthereto by tipping paper. In conventional filter cigarettes, the filterusually consists of a plug of cellulose acetate tow wrapped in porousplug wrap. Filter cigarettes with multi-component filters that comprisetwo or more segments of filtration material for the removal ofparticulate and gaseous components of the mainstream smoke are alsoknown.

To enhance the flavour of the mainstream smoke, it is known to providefilter cigarettes with filters that include flavourants. For example,US-A-2003/0159703 discloses a cigarette filter including flavouredcarbon particles which are formed by applying a liquid flavourant ontoactivated carbon particles so that the flavourant may be adsorbed orabsorbed by the activated carbon. It has also been proposed to includeflavourants in the form of plant material, such as leaves, seeds orroots, from one or more aromatic plants.

It would be desirable to provide means for releasing flavour for asmoking article that, in use, provides improved flavour enhancement, andin particular improved mint and menthol flavour delivery, to a consumer.Furthermore, it would be desirable to provide means for releasingflavour for a smoking article that minimises loss of flavour prior tosmoking, for example during storage of the smoking article.

According to the present invention there is provided a flavour granulesuitable for use in a smoking article, the flavour granule comprising aporous support material, a liquid flavourant, particles of plantmaterial and at least one binder. The present invention also provides asmoking article comprising a plurality of flavour granules according tothe invention. The flavour granules may be incorporated into a rod ofsmokable material, a filter or any other suitable portion or componentof the smoking article.

According to the present invention there is also provided a filter for asmoking article comprising a flavour release segment including aplurality of flavour granules, wherein the flavour granules comprise aporous support material, a liquid flavourant, particles of plantmaterial and at least one binder.

According to the present invention there is also provided a smokingarticle comprising a wrapped rod of smokable material and a filteraccording to the present invention attached to the rod of smokablematerial, preferably by tipping paper. Preferably, the smoking articleis a filter cigarette.

Flavour granules and filters according to the present invention mayadvantageously be used in filter cigarettes and other smoking articlesin which tobacco material or another combustible material is combustedto form smoke. Flavour granules and filters according to the presentinvention may also be used in smoking articles in which material isheated to form an aerosol, rather than combusted. In one type of heatedsmoking article, tobacco material or another aerosol forming material isheated by one or more electrical heating elements to produce an aerosol.In another type of heated smoking article, an aerosol is produced by thetransfer of heat from a combustible or chemical heat source to aphysically separate aerosol forming material, which may be locatedwithin, around or downstream of the heat source.

As used herein, the term ‘smoke’ is used to describe smoke produced bycombustible smoking articles, such as filter cigarettes, and aerosolsproduced by non-combustible smoking articles, such as heated smokingarticles of the types described above.

The flavour granules of the present invention are discrete, solidgranules formed of an agglomerate of a porous support material, a liquidflavourant, particles of plant material and at least one binder.

When incorporated into a smoking article, both the liquid flavourant andthe plant material in the flavour granules release flavour duringsmoking thereby altering the flavour characteristics of the smoke.Advantageously, the composition of the flavour granules can be varied inorder to tailor the flavour profile of the smoking article into whichthe flavour granules are incorporated. For example, the liquidflavourant and the plant material can be selected such that eachreleases flavour at a different time during smoking. Alternatively or inaddition, the liquid flavourant and the plant material can be varied toalter the type of flavour or flavours released during smoking.

As used herein, the term “porous support material” is used to denote aporous material that is capable of retaining a liquid flavourant withinthe pores of its structure, either by adsorption, absorption, or bothadsorption and absorption. The flavour granules of the present inventioncomprise a porous support material loaded with a liquid flavourant.

The inclusion of a porous support material and a liquid flavourant inflavour granules according to the present invention is advantageoussince the liquid flavourant can be effectively trapped within the poresof the porous support material, thereby preventing or reducing loss ofthe liquid flavourant prior to smoking, for example by volatilisation.This, together with the other components of the flavour granules of thepresent invention, advantageously enables a larger volume of the liquidflavourant to be provided in a smoking article, resulting in increasedflavour delivery during smoking.

As described further below, the inclusion of particles of plant materialin the flavour granules of the present invention also improves retentionof the liquid flavourant within the pores of the porous supportmaterial.

Flavour granules according to the present invention preferably comprisea particulate porous support material. Preferably, the porous supportmaterial is ground before being incorporated into the flavour granulesin order to achieve a consistent particle size.

Preferably, the flavour granules comprise between about 10% and about40% by weight porous support material, more preferably between about 15%and about 35% by weight porous support material and most preferablybetween about 20% and about 30% by weight porous support material (basedon the weight of the final flavour granules). As used herein, the term“final flavour granules” is used to refer to the flavour granules afterformation and drying thereof.

Preferably, the density of the porous support material is between about0.2 g/cm³ (grams per cubic centimetre) and about 0.8 g/cm³, morepreferably between about 0.3 g/cm³ and about 0.5 g/cm³. Preferably, theBET surface area of the porous support material is between about 800m²/g (square metres per gram) and about 3000 m²/g, more preferablybetween about 1000 m²/g and about 1300 m²/g.

Preferably, the porous support material is an inorganic porous material,more preferably an inorganic porous adsorbent material. Preferred poroussupport materials for use in flavour granules according to the presentinvention include, but are not limited to, activated carbon, polymericresin, silica, clay and zeolites, for example zeolites having a highsilica/alumina ratio.

The use of activated carbon as the porous support material in flavourgranules according to the present invention is particularly preferred.This is because the activated carbon advantageously initially acts as areservoir for the liquid flavourant and then, once the liquid flavouranthas been released, may also act as an adsorbent to reduce certaingaseous smoke constituents.

As used herein, the term “liquid flavourant” is used to denote a liquidsubstance that provides flavour to the smoke produced by a smokingarticle during smoking. The liquid flavourant is trapped within thepores of the porous support material and retained therein until smoking.The heat generated during smoking causes the volatilisation of theliquid flavourant and the resultant volatilised flavour compounds arereleased from the porous support material into the smoke. The flavoursreleased by the volatilisation of the liquid flavourant enhance theflavours released from the particles of plant material in the flavourgranules of the present invention to provide increased flavour deliveryduring smoking.

Preferably, the flavour granules comprise at least about 10% by weightliquid flavourant, more preferably at least about 15% by weight liquidflavourant and most preferably at least about 20% by weight liquidflavourant (based on the weight of the final flavour granules).Preferably, the flavour granules comprise up to about 30% by weightliquid flavourant, more preferably up to about 40% by weight liquidflavourant.

Particularly preferably, the flavour granules comprise between about 10%and about 40% by weight liquid flavourant, more preferably between 15%and 30% by weight liquid flavourant and most preferably between about20% and about 30% by weight liquid flavourant.

The amount of porous support material in flavour granules according tothe present invention may be adjusted depending on the amount of liquidflavourant incorporated therein, so that all of the liquid flavourantcan be retained within the pores of the porous support material.

Suitable liquid flavourants for use in the flavour granules of thepresent invention are well known to the skilled person. The liquidflavourant may include one or more natural flavourants, one or moresynthetic flavourants, or a combination of natural and syntheticflavourants.

The liquid flavourant may comprise a liquid flavour extract or maycomprise a solid flavour extract dissolved in a suitable liquid solvent.Where a suitable liquid solvent is used, some of this liquid solvent maybe removed from the flavour granules after formation thereof, forexample during a drying step.

Suitable flavours to be provided by the liquid flavourant include, butare not limited to, natural or synthetic menthol, peppermint, spearmint,coffee, tea, spices (such as cinnamon, clove and ginger), cocoa,vanilla, fruit flavours, chocolate, eucalyptus, geranium and linalool.

Preferably, the liquid flavourant includes an essential oil, or amixture of one or more essential oils. An “essential oil” is a volatileoil having the characteristic odour and flavour of the plant from whichit is obtained. Suitable essential oils for inclusion in the flavourgranules of the present invention include, but are not limited to,peppermint oil and spearmint oil.

The one or more essential oils may be provided in a solution of, forexample, ethanol.

Where the liquid flavourant comprises an essential oil, the essentialoil may be obtained from the same type of plant as the particles ofplant material in the flavour granules, so that the flavours releasedfrom the liquid flavourant and plant material during smoking enhanceeach other. Alternatively, the essential oil may be obtained from adifferent type of plant than the particles of plant material in theflavour granules, so that multiple flavours are released from theflavour granules during smoking.

As used herein, the term “plant material” is used to denote a materialconsisting of one or more parts of a plant. The plant material is groundor otherwise reduced in size to provide a particulate material.

Preferably, the flavour granules in the flavour release segment comprisebetween 15% and 35% by weight plant material, more preferably between20% and 30% by weight plant material (based on the weight of the finalflavour granules).

The flavour granules may include particles of any plant material that iscapable of releasing flavour into smoke produced by a smoking article.Preferably, the plant material is non-tobacco plant material, so thatthe flavour granules enrich the smoke with non-tobacco flavour. Theflavour granules may comprise particles formed from any suitable part ofa plant, including but not limited to the leaves, stem, root, flower andfruit. The flavour granules may include plant material from one or moreplants.

Preferably, the flavour granules comprise particles of plant leaf. Morepreferably, the flavour granules comprise particles of non-tobacco plantleaf. In preferred embodiments of the present invention, the flavourreleased from the plant leaf is provided by volatile compounds, such asoils, contained therein. Prior to smoking, the volatile compounds tendto remain trapped within the plant leaf, but are volatilised duringsmoking, thereby enriching the smoke with flavour. The flavours releasedfrom the plant leaf enhance and complement the flavours released fromthe liquid flavourant loaded into the porous support material, therebyincreasing the overall flavour delivery during smoking. The flavourcharacteristics of the smoke can therefore be altered depending on theplant leaf selected for inclusion in the flavour granules.

In particularly preferred embodiments of the present invention, theparticles of plant material comprise herbaceous material, such as herbleaf.

The terms “herbaceous material” and “herb leaf” are used to denotematerial and leaf, respectively, from an herbaceous plant. An“herbaceous plant” is an aromatic plant, the leaves or other parts ofwhich are used for medicinal, culinary or aromatic purposes and arecapable of releasing flavour into smoke produced by a smoking article.The flavour granules of the present invention may comprise herbaceousmaterial from one or more perennial or annual herbaceous plants. Forexample, the flavour granules may comprise herb leaf or other herbaceousmaterial from herbaceous plants including, but not limited to, mints,such as peppermint and spearmint, lemon balm, basil, cinnamon, lemonbasil, chive, coriander, lavender, sage, tea, thyme and carvi. The term“mints” is used to refer to plants of the genus Mentha.

In particularly preferred embodiments of the present invention, theflavour granules comprise particles of mint leaf, more preferablyparticles of peppermint leaf. Suitable types of mint leaf may be takenfrom plant varieties including but not limited to Mentha piperita,Mentha arvensis, Mentha niliaca, Mentha citrata, Mentha spicata, Menthaspicata crispa, Mentha cordifolia, Mentha longifolia, Mentha pulegium,Mentha suaveolens, and Mentha suaveolens variegate.

Preferably, the oil content of the mint leaf is at least about 0.6% byweight. The inclusion of particles of mint leaf in flavour granules ofaccording to the present invention advantageously provides an improvedway of imparting mint and menthol flavours to the smoke of a smokingarticle. Smoking articles according to the present invention withfilters comprising flavour granules comprising particles of peppermintleaf advantageously provide enhanced mint and menthol flavours comparedto conventional menthol cigarettes.

The term “mint flavour” is used to refer to the flavour or the flavourextract present in mint plants, such as a peppermint plant andspearmint. The term “menthol” is used to refer to a specific flavourcomponent present in peppermint oil and other mint oils. Menthol can beextracted from peppermint and other mint oils or made synthetically andif desired, can be used as the liquid flavourant in the flavour granulesof the present invention, as set out above.

Preferably, the plant material in the flavour granules is ground inorder to provide a particulate material suitable for agglomeration withthe other components of the flavour granules. However, in certainembodiments a suitable particle size may be achieved by shredding orcutting the plant material. Preferably, the particles of plant materialhave an average particle size of less than about 600 microns (μm), morepreferably of less than about 400 microns (μm) and most preferably ofless than about 300 microns (μm). Preferably, the particles of plantmaterial have an average particle size of greater than about 25 microns(μm) and more preferably of greater than about 65 microns (μm).Particularly preferably, the particles of plant material have an averageparticle size between about 25 microns (μm) and about 600 microns (μm),more preferably between about 65 microns (μm) and about 300 microns(μm).

Preferably, the plant material, such as plant leaf, is dried to amoisture content of between about 6% and about 15% by weight, morepreferably of between about 8% and about 12% by weight and mostpreferably of between about 8% and about 10%.

The particles of plant material may act as a barrier around the poroussupport material loaded with liquid flavourant. This advantageouslyensures a minimum loss of liquid flavourant from the porous supportmaterial during storage of filters and smoking articles according to thepresent invention, and may also allow for the porous support material tobe initially loaded with more liquid flavourant. This in turn maximisesthe flavour release from the flavour granules of the present inventioninto the smoke during smoking.

With certain combinations of liquid flavourant and plant material, theflavour from the liquid flavourant may be released into the smoke at adifferent time after the commencement of smoking than the flavourreleased from the plant material. This may advantageously providerelatively consistent levels of flavour delivery during smoking andallows the flavour profile of smoking articles according to the presentinvention to be tailored or adjusted. For example, flavour may bereleased into the smoke firstly from the particles of plant material andthen secondly from the liquid flavourant.

In a particularly preferred embodiment of the present invention, theflavour granules comprise a combination of particles of peppermint leafand menthol as the liquid flavourant. As described above, menthol is oneof the major components of peppermint oil and can be made syntheticallyor extracted from peppermint oil using known extraction techniques. Inthis particularly preferred embodiment, the mint and menthol flavoursenhance and complement each other and the flavour granules provide anincreased and sustained delivery of flavour to the smoker duringsmoking.

The flavour granules of the invention comprise at least one binder. Thebinder helps to hold the components of the flavour granule together andmay also be used to adjust the viscosity or flow properties of theagglomerate during formation of the flavour granules. Suitable bindersfor use in the flavour granules of the present invention are well knownto the skilled person.

The flavour granules may include an organic binder, such as for examplecarboxymethylcellulose, microcrystalline cellulose or polyvinylacetate,polyethylene glycol, polyethylene oxide, gelatine, starch, sugar,hydroxylethyl/methyl cellulose.

Alternatively, or in addition, the flavour granules may include aninorganic binder, such as for example water. Preferably, water isincluded as a binder during formation of the flavour granules.

It will be appreciated that flavour granules according to the presentinvention may include a combination or one or more organic binders andone or more inorganic binders. It will also be appreciated that flavourgranules according to the invention may include one or more solidbinders or one or more liquid binders or a combination of one or moresolid binders and one or more liquid binders.

Some of the binder included during formation of the flavour granules maybe removed from the flavour granules once they have been formed. Forexample, where water is included as an inorganic liquid binder duringformation of the flavour granules, a large proportion of the water maybe removed by drying the flavour granules subsequent to the formationthereof.

Preferably, the final flavour granules have a total binder content ofbetween about 15% and about 35% by weight total binder, more preferablybetween about 20% and about 30% by weight and most preferably betweenabout 22.5% and about 27.5% by weight (based on the weight of the finalflavour granules).

The flavour granules may be formed into any suitable shape, but arepreferably substantially cylindrical or spherical. The average diameterof the flavour granules is preferably between about 0.1 mm and about 2.5mm, more preferably between about 0.3 mm and about 1.0 mm, even morepreferably between about 0.5 mm and about 0.6 mm. Preferably, theparticle size distribution of the flavour granules is minimised. Theparticle size distribution may depend upon, amongst other things, theweight ratio of solids to liquid binder (for example, water) used in thegranule formation process. Preferably, the amount of liquid binder usedin the granule formation process is approximately equal to the amount ofsolids used therein, or there is slightly more liquid binder thansolids.

Optionally, the flavour granules may further comprise a coating. Apreferred coating may be formed from low molecular weight chitosansolution (0.5 to 1.0%). It has been found that the provision of acoating on the outer surface of the flavour granules advantageouslyresults in a significant reduction in migration and volatilisation ofvolatile flavours from the liquid flavourant and particles of plantmaterial in the flavour granules prior to smoking. The provision of acoating further enhances the effect of trapping the liquid flavourantwithin the pores of the porous support material such that the undesiredpremature release of flavour from the flavour granules can be minimised.

Flavour granules according to the present invention may be producedusing known extrusion, spheronisation or high shear granulationprocesses. Details of suitable extrusion and spheronisation techniquescan be found, for example, in “Extrusion-Spheronisation—A LiteratureReview” by Chris Vervaet et al, 1995 International Journal ofPharmaceutics 116:131-146.

If desired, additional reagents may be incorporated into the mixture forforming the flavour granules in order to aid the extrusion,spheronisation or granulation process, for example, by preventing orminimising separation of the liquid from the solid or by improving flowproperties of the mixture. Suitable extrusion, spheronisation andgranulation aiding reagents are well known to the skilled person.

Once formed, the flavour granules will typically need to undergo adrying step in order to at least partially remove one or more solventsor binders present therein.

If it is desired to further increase the flavour loading of the flavourgranules, further liquid flavourant may be incorporated into or onto theflavour granules after drying thereof.

Where a coating is provided on the flavour granules, this may be appliedto the granules obtained from the extrusion, spheronisation orgranulation process after drying thereof using any suitable apparatussuch as for example a fluidised bed sprayer. Suitable fluidised bedsprayers are available from Glatt GmbH, Germany.

Flavour granules according to the present invention may advantageouslybe incorporated into a wide variety of different types of smokingarticle. For example, the flavour granules may be incorporated intocombustible smoking articles, such as filter cigarettes, having a rod oftobacco cut filler or other smokable material, which is combusted duringsmoking. Alternatively, the flavour granules may be incorporated intoheated smoking articles of the type described above in which material isheated to form an aerosol, rather than combusted. For example, flavourgranules according to the present invention may be incorporated into aheated smoking article comprising a combustible heat source, such asthat disclosed in WO-A-2009/022232, which comprises a combustible heatsource and an aerosol-generating substrate downstream of the combustibleheat source. Flavour granules according to the present invention mayalso be incorporated into heated smoking articles comprisingnon-combustible heat sources, for example, chemical heat sources orelectrical heat sources such as electrical resistive heating elements.

Flavour granules according to the present invention may be incorporatedinto any suitable portion or component of a smoking article. Forexample, the flavour granules may be incorporated into a rod of smokablematerial or filter of a combustible smoking article, such as a filtercigarette, or may incorporated into an aerosol-generating substrate orfilter of a heated smoking article. It will be appreciated that flavourgranules according to the present invention may be incorporated intomore than one portion or component of a smoking article.

Smoking articles according to the present invention comprising aplurality of flavour granules may comprise any number of flavourgranules that is suitable to provide flavour enhancement to the smokethereof during smoking. For example, smoking articles according to theinvention may comprise between about 2 and about 30,000 flavourgranules, for example between about 2 and 20,000 flavour granules.

Filters according to the present invention comprising a flavour releasesegment including a plurality of flavour granules may be single segmentfilters, consisting of the flavour release segment only. Alternatively,filters according to the invention may be multi-component filterscomprising two or segments. For example, filters according to thepresent invention may be multi-component filters further comprising atleast one of: a rod end segment upstream of the flavour release segmentand a mouth end segment downstream of the flavour release segment.

Throughout the specification, the terms “upstream” and “downstream” areused to describe the relative positions of segments of filters accordingto the present invention in relation to the direction of the smoke drawnthrough the filters during use. For example, where the flavour releasesegment is upstream of a mouth end segment, the smoke is drawn firstthrough the flavour release segment and then through the mouth endsegment.

Filters according to the present invention may comprise flavour releasesegments including any number of flavour granules that is suitable toprovide flavour enhancement to smoke drawn through the filter duringsmoking. For example, filters according to the invention may compriseflavour release segments including between about 2 and about 25,000flavour granules, for example between about 2 and 15,000 flavourgranules.

The mouth end segment of multi-component filters according to thepresent invention may, in some embodiments, advantageously preventflavour granules in the flavour release segment, or portions thereof,from reaching the mouth of a smoker during smoking.

Preferably, the mouth end segment comprises filtration material. Morepreferably, the mouth end segment comprises filtration material that hassubstantially no particulate phase filtration efficiency or very lowparticulate phase filtration efficiency. The mouth end segment may, forexample, comprise cellulosic material, such as cellulose acetate tow, orother suitable fibrous filtration material of low filtration efficiency.Where the mouth end segment is formed of fibrous filtration material,the fibres therein may extend along substantially the entire length ofthe mouth end segment and be substantially aligned in the longitudinaldirection of the filter. Alternatively, the fibres may extend part wayalong the length of the plug and be randomly oriented relative to thelongitudinal axis of the filter.

Where the mouth end segment comprises filtration material, the length ofthe mouth end segment is preferably between about 3 mm and about 12 mm,more preferably between about 6 mm and about 8 mm.

Filters according to the present invention may comprise a mouth endcavity downstream of the flavour release segment. For example, incertain embodiments, multi-component filters according to the presentinvention may further comprise a mouth end cavity downstream of themouth end segment described above. The mouth end cavity may be formedby, for example, tipping paper circumscribing the filter.

The rod end segment of multi-component filters according to theinvention preferably comprises fibrous filtration material. The rod endsegment may, for example, comprise cellulosic material, such ascellulose acetate tow, or other suitable fibrous filtration materialssuch as paper. Where the rod end segment is formed of fibrous filtrationmaterial, the fibres therein may extend along substantially the entirelength of the rod end segment and be substantially aligned in thelongitudinal direction of the filter. Alternatively, the fibres mayextend part way along the length of the plug and be randomly orientedrelative to the longitudinal axis of the filter. The inclusion of a rodend segment comprising filtration material advantageously providesadditional filtration efficiency.

Alternatively or in addition, the rod end segment may comprise at leastone sorbent capable of removing at least one gas phase constituent frommainstream smoke drawn through the filter. Preferably, the at least onesorbent is selected from the group consisting of activated carbon,activated alumina, zeolites, sepiolites, molecular sieves and silicagel.

At least one of the mouth end segment and the rod end segment mayinclude one or more flavourants, preferably one or more liquidflavourants, to further enhance flavour delivery to the smoker duringsmoking. Where the mouth end segment and the rod end segment bothcomprise at least one flavourant, the at least one flavourant in themouth end segment may be the same as or different to the at least oneflavourant in the rod end segment. Furthermore, the liquid flavourantsin the mouth end segment and the rod end segment may be the same as ordifferent to the liquid flavourant in the flavour granules in theflavour release segment of the filter.

For example, at least one of the mouth end segment and the rod endsegment may comprise a plug of filtration material including one or morethreads impregnated with liquid flavourant. The one or more threads maybe made from cellulose acetate yarn, rayon, cotton, paper, or any otherhydrophilic textile or non-textile material capable of absorbing oradsorbing the liquid flavourant. The threads may be coloured, forexample, to indicate the type of flavourant impregnated therein. If morethan one thread is provided, the threads may be the same or differentcolours and may be impregnated with the same or different liquidflavourants. Preferably, the threads are between about 0.6 mm and about2.0 mm in diameter, more preferably about 0.8 mm in diameter. Filterplugs comprising flavourant bearing threads suitable for use inmulti-component filters according to the present invention, and methodsand apparatuses for producing such plugs, are described in U.S. Pat.Nos. 4,281,671 and 7,074,170 and are available from the AmericanFiltrona Company, Richmond, Va., USA.

Alternatively or in addition, at least one of the mouth end segment andthe rod end segment may include a plurality of beads impregnated withliquid flavourant. The beads may be formed from, for example, acellulosic material bonded with a polyvinyl acetate binder, or fromtobacco powder bonded with microcrystalline cellulose. Beads suitablefor use in multi-component filters according to the present inventionare manufactured and sold under the brand Viscopearls® by Rengo Co.Ltd., Japan. Methods and apparatuses for producing such beads are alsodescribed in Japanese Patent Application No. 10182842. The beads may beof the same or different diameters and colours. The colour of the beadsmay, for example, indicate the type of flavourant with which they areimpregnated. Preferably, the beads are between about 0.2 mm and about 2mm in diameter.

Liquid flavourants for use in the mouth end and rod end segments ofmulti-component filters according to the present invention may includeone or more natural flavourants, synthetic flavourants, or a combinationof natural and synthetic flavourants. Suitable flavours to be providedby liquid flavourants in the mouth end and rod end segments ofmulti-component filters according to the present invention include, butare not limited to, those previously described above for the liquidflavourant in the flavour granules thereof.

In preferred embodiments of the present invention in which the flavourgranules comprise particles of peppermint leaf and menthol as the liquidflavourant, at least one of the mouth end segment and the rod endsegment of the multi-component filter preferably comprises a liquidnatural or synthetic menthol flavourant. In such embodiments, theprovision of a menthol flavourant in the rod end segment advantageouslyfurther enhances the flavour released into smoke drawn through thefilter during smoking and complements the menthol and mint flavoursreleased downstream into the smoke by the particles of peppermint leafand menthol in the flavour granules located in the flavour releasesegment.

Multi-component filters according to the present invention may furthercomprise a second flavour release segment to provide further flavourenhancement to the smoker during smoking. The second flavour releasesegment may include a plurality of flavour granules according to theinvention. Alternatively or in addition, the second flavour releasesegment may include tobacco leaf or non-tobacco plant leaf, or one ormore liquid flavourants in any of the forms described above in relationto the mouth end segment and the rod end segment. The second flavourrelease segment may be provided upstream or downstream of the firstflavour release segment.

Multi-component filters according to the present invention may beproduced by forming separate continuous rods comprising multiple unitsof each individual segment of the multi-component filter and thencombining these separate rods in a known manner in one or more stages toform a continuous filter rod comprising multiple units of themulti-component filter. The continuous filter rod may then besubsequently severed at regular intervals by a cutting mechanism toyield a succession of discrete multi-component filters according to theinvention.

In a first aspect of the present invention, the plurality of flavourgranules in the flavour release segment of the filter is distributed ina plug of fibrous filtration material, such as cellulose acetate tow orpaper. Preferably, the flavour granules are substantially evenlydistributed along the length of the plug of fibrous filtration material.

The fibres in the fibrous filtration material may be substantiallyaligned in the longitudinal direction of the filter and extend alongsubstantially the entire length of the plug of fibrous filtrationmaterial. Alternatively, the fibres in the fibrous filtration materialmay be randomly oriented and extend part way along the length of theplug of fibrous filtration material. Optionally, a filter plasticisermay be applied to the fibrous filtration material in a conventionalmanner, by spraying it onto the separated fibres. Preferably, the filterplasticiser is applied to the fibrous filtration material before theflavour granules are distributed therein.

In smoking articles according to the first aspect of the invention, theflavour segment is preferably between about 5 mm and about 22 mm inlength, more preferably between about and 10 mm about 15 mm in length,most preferably about 12 mm in length.

Preferably, filters according to the first aspect of the presentinvention further comprise a mouth end segment downstream of the flavourrelease segment. A mouth end cavity may optionally be provideddownstream of the mouth end segment. The mouth end cavity may be formedwhen the filter is attached to a rod of smokable material by, forexample, tipping paper to form a smoking article according to thepresent invention. Where a mouth end cavity is provided downstream ofthe mouth end segment, the length of the mouth end segment is preferablybetween about 3 mm and about 4 mm.

In a second aspect of the present invention, the flavour release segmentcomprises a cavity at least partially filled with flavour granules. Thecavity is provided between an upstream segment, for example any of therod end segments described above, and a downstream segment, for exampleany of the mouth end segments described above. Preferably, between about40% and about 100% of the volume of the cavity is filled with flavourgranules, more preferably between about 60% and about 80% of the volumeof the cavity. Cavity filters according to the second aspect of theinvention may be produced using known machinery for producing charcoalfilters, such as that described in EP-A-1,571,933. Such machinery isavailable from Filtrona International Ltd., Great Britain.

In filters according to the second aspect of the invention, the flavourrelease segment is preferably between about 2 mm and about 12 mm inlength, more preferably between 3 mm and 8 mm and most preferablybetween 4 mm to 6 mm.

The loading of flavour granules in the flavour release segment ispreferably between about 2 mg/mm and about 20 mg/mm for a filter havinga diameter of between about 7.5 mm and about 7.85 mm, more preferablybetween about 5 mg/mm and about 16 mg/mm, most preferably between about8 mg/mm and about 16 mg/mm. The normalised loading (mg per mm) willtypically be higher where the flavour granules are provided in a cavityin accordance with the second aspect of the present invention than whenthe flavour granules are distributed through a plug of fibrousfiltration material in accordance with the first aspect of the presentinvention. Preferably, the total loading of flavour granules within theflavour release segment is between about 20 mg and about 200 mg, morepreferably between about 50 mg and about 180 mg and most preferablybetween about 75 mg and about 150 mg.

Combustible smoking articles according to the present inventionpreferably comprise a wrapped rod of tobacco cut filler or othersmokable material and a filter according to the present inventionincluding a flavour release segment comprising a plurality of flavourgranules.

In certain embodiments, the wrapper used to wrap the tobacco rod may becoated with a solution of encapsulated flavours in beta-cyclodextrin,which odorises the mainstream smoke during smoking. A suitable exampleof such a coating is Emanate® (available from V. Mane Fils, France)which is a product consisting of a range of beta-cyclodextrin inclusioncomplexes such as Eugenol.

Preferably, smoking articles according to the present invention have atotal nicotine free dry particulate matter (NFDPM) or “tar” delivery ofup to about 10 mg, more preferably up to about 6 mg. The “tar” deliverymay be as low as 1 mg, more preferably as low as 0.1 mg. Preferably, the“tar” delivery is between 0.1 mg and 10 mg, more preferably between 1 mgand 10 mg or 0.1 mg and 6 mg and most preferably between 1 mg and 6 mg.

Preferably, the overall length of smoking articles according to thepresent invention is between about 70 mm and about 128 mm, morepreferably about 84 mm.

Preferably, the external diameter of filters and smoking articlesaccording to the present invention is between about 5 mm and 8.5 mm,more preferably about 7.9 mm.

Preferably, the overall length of filters according to the presentinvention is between about 18 mm and about 36 mm, more preferably about27 mm.

Where filters according to the invention are multi-component filters,the length of each individual segment of the filters is preferablybetween about 5 mm and about 22 mm.

Smoking articles according to the present invention may be packaged incontainers, for example in soft packs or hinge-lid packs, with an innerliner coated with one or more flavourants.

The invention will be further described, by way of example only, withreference to the accompanying drawings, in which:

FIG. 1 shows a side view of a filter cigarette comprising a singlesegment filter according to a first embodiment, of the first aspect ofthe present invention;

FIG. 2 shows a side view of a filter cigarette comprising amulti-component filter according to a second embodiment of the firstaspect of the present invention; and

FIG. 3 shows a side view of a filter cigarette comprising amulti-component filter according to an embodiment of the second aspectof the present invention.

The filter cigarettes shown in FIGS. 1 to 3 have several components incommon and these components have been given the same reference numerals.In each of the side views, portions have been broken away to illustrateinterior details of the filter.

Each filter cigarette generally comprises an elongate, cylindricalwrapped tobacco rod 2 attached at one end to an axially aligned,elongate, cylindrical, filter 4. The wrapped tobacco rod 2 and thefilter 4 are joined in a conventional manner by tipping paper 6, whichcircumscribes the entire length of the filter and an adjacent portion ofthe wrapped tobacco rod 2. To mix ambient air with mainstream smokeproduced during combustion of the wrapped tobacco rod 4, a plurality ofannular perforations 8 are provided through the tipping paper 6 at alocation along the filter 4.

Each filter 4 includes a flavour release segment 14 comprising aplurality of flavour granules having a total weight of approximately 25mg. The flavour granules are substantially spherical and have an averagediameter of about 0.8 mm.

The flavour granules comprise 20-30% by weight of porous supportmaterial (ground activated carbon), 20-30% by weight of a liquidflavourant (solution of menthol in ethanol), 20-30% by weight ofparticles of plant material (ground peppermint leaf), 20-30% by weightof a solid organic binder and around 10% by weight of a liquid inorganicbinder (water).

In order to produce the flavour granules, the porous support material ismixed with the liquid flavourant, forming a flavoured porous supportmaterial. The flavoured porous support is then mixed with the particlesof plant material, the solid organic binder and the liquid inorganicbinder to form a homogeneous paste, which is then extruded to formstrands having an average diameter of 1 mm.

The strands are spheronised on a cylindrical plate to form sphereshaving an average diameter of 0.8 mm. The resultant spheres are dried toremove the majority of the liquid inorganic binder and solvent from theliquid flavourant. The weight ratio of solids to liquid binder (water)in the spheres prior to drying is around 1:1.06.

Once the spheres are dried, a coating of low molecular weight chitosansolution may be optionally applied to the outer surfaces of the finalflavour granules in a fluidised bed sprayer.

An example of a suitable process for forming the flavour granules is setout below.

The filter 4 of the filter cigarette 10 according to the firstembodiment of the invention shown in FIG. 1 is a single segment filterconsisting of a flavour release segment 14 adjacent to and abutting thewrapped tobacco rod 2. The flavour release segment 14 comprises a plugof cellulose acetate tow with a plurality of flavour granulessubstantially evenly distributed therein.

The filter cigarette 20 shown in FIG. 2 has a multi-component filter 4that includes three segments in abutting end-to-end relationship: amouth end segment 12, distant from the tobacco rod 2; a flavour releasesegment 14 located upstream of the mouth end segment; and a rod endsegment 16, located upstream of the flavour release segment 14 andadjacent to and abutting the wrapped tobacco rod 2.

The mouth end segment 12 comprises a plug of cellulose acetate tow oflow filtration efficiency plasticised with glycerol triacetate. Theflavour release segment 14 is of the same construction as thatpreviously described above for the filter cigarette 10 shown in FIG. 1.

The rod end segment 16 comprises a plug of cellulose acetate tow ofmedium to high filtration efficiency that, in use, partially filters outparticulate phase components of the mainstream smoke.

In alternative embodiments of the present invention (not shown), atleast one of the mouth end segment 12 and the rod end segment 16 of themulti-component filter 4 of the filter cigarette 20 shown in FIG. 2 mayfurther comprise at least one liquid flavourant. For example, one orboth of the mouth end segment 12 and the rod end segment 16 may compriseone or more threads impregnated with a liquid flavourant or a pluralityof beads impregnated with a liquid flavourant. Alternatively or inaddition, at least one of the mouth end segment 12 and the rod endsegment 16 of the multi-component filter 4 may comprise at least onesorbent capable of removing gas phase constituents from mainstream smokedrawn through the filter 4. The at least one sorbent may be, forexample, activated carbon, activated alumina, zeolites or sepiolitesprovided on the cellulose acetate tow.

The filter cigarette 30 shown in FIG. 3 has a multi-component filter 4similar in construction to the multi-component filter 4 of the filtercigarette 20 shown in FIG. 2, with three segments in abutting end-to-endrelationship: a mouth end segment 12, distant from the tobacco rod 2; aflavour release segment 24 located upstream of the mouth end segment 12;and a rod end segment 16, located upstream of the flavour releasesegment 24 and adjacent to and abutting the wrapped tobacco rod 2. Themouth end segment 12 and the rod end segment 16 are of the sameconstruction as those previously described for the filter cigarette 20shown in FIG. 2. The flavour release segment 24 comprises a cavitycontaining a plurality of flavour granules.

To form the filter cigarettes 10, 20, 30 according to the embodiments ofthe present invention shown in FIGS. 1 to 3, the filters 4 are producedand then joined to the wrapped tobacco rods 2, which are produced in aconventional manner, by the tipping paper 6 using known filter cigarettemaking equipment.

To produce the multi-component filters 4 of the filter cigarettes 20, 30shown in FIGS. 2 and 3, separate continuous rods comprising multipleunits of each segment 12, 14, 24, 16 of the multi-component filter 4 areproduced in a known manner and then combined to form a continuous filterrod comprising multiple units of the multi-component filter 4. Thecontinuous filter rod is then severed at regular intervals by a cuttingmechanism to yield a succession of discrete multi-component filters.

The following example describes a method for producing flavour granulesfor use in the flavour segment of filters according to the presentinvention, including any of the embodiments described above:

EXAMPLE

Flavour granules are formed from an agglomerate of the components shownbelow in Table 1 in the amounts indicated in the column headed ‘Amountbefore drying (g)’.

To produce the flavour granules, the activated carbon and the mentholsolution are first mixed together to form a menthol-flavoured activatedcarbon. The menthol flavoured activated carbon is then mixed with theground peppermint leaf, the Avicel PH101® and the water to form ahomogeneous paste, which is then extruded to form strands having anaverage diameter of 1 mm. As described above, the strands arespheronised on a cylindrical plate to form spheres having an averagediameter of about 0.8 mm and then dried to remove the majority of thewater and the ethanol from the menthol solution.

TABLE 1 Amount (g) Amount (g) % by weight before after after ComponentFunction drying drying drying Activated carbon Porous 25.0 25.0 23.3%support material Menthol solution Liquid 25.0 22.4 20.8% (menthol 85%;flavourant ethanol 15%) Avicel PH101 ® Organic 25.0 25.0 23.3%(microcrystalline binder cellulose) Ground Plant 25.0 25.0 23.3%peppermint leaf material (Mentha piperita) Water Inorganic 103.2 10.0 9.3% binder TOTAL 203.2 107.4  100% Avicel PH 101 ® is available fromSigma Aldrich.

1. A flavour granule for a smoking article, the flavour granulecomprising: a porous support material; a liquid flavourant; particles ofplant material; and at least one binder.
 2. A filter for a smokingarticle comprising a flavour release segment including a plurality offlavour granules according to claim
 1. 3. A filter according to claim 2wherein the plant material comprises herb leaf.
 4. A filter according toclaim 2 wherein the liquid flavourant comprises at least one of: anessential oil; and natural or synthetic menthol.
 5. A filter accordingto claim 2 wherein the flavour granules comprise at least 20% by weightliquid flavourant.
 6. A filter according to claim 2 wherein the poroussupport material is activated carbon.
 7. A filter according to claim 2wherein the flavour granules further comprise a coating.
 8. A filteraccording to claim 2 wherein the flavour release segment includes a plugof fibrous filtration material in which the flavour granules aredistributed and the fibrous filtration material comprises fibres thatare substantially aligned in the longitudinal direction of the filterand that extend along substantially the entire length of the plug offibrous filtration material.
 9. A filter according to claim 2 whereinthe flavour release segment includes a plug of fibrous filtrationmaterial in which the flavour granules are distributed and the plug offibrous filtration material comprises randomly oriented fibres thatextend part way along the length of the plug of fibrous filtrationmaterial.
 10. A filter according to claim 2 further comprising at leastone of: a mouth end segment downstream of the flavour release segment;and a rod end segment upstream of the flavour release segment.
 11. Afilter according to claim 10 wherein one or both of the mouth endsegment and the rod end segment comprise an additional liquidflavourant.
 12. A filter according to claim 2 wherein the flavourrelease segment includes a cavity at least partially filled with theflavour granules.
 13. A smoking article comprising: a wrapped rod ofsmokable material; and a filter according to claim 2 attached to thewrapped rod of smokable material by tipping paper.
 14. A smoking articlecomprising a plurality of flavour granules according to claim
 1. 15. Asmoking article according to claim 14 further comprising a rod ofsmokable material wherein the flavour granules are dispersed within therod of smokable material.
 16. A filter according to claim 3, wherein theherb leaf comprises peppermint leaf.